Hitherto, there has been known a microwave oven which includes a temperature detection device inside an air guide as a passage through which an exhaust air stream flows in order to detect the temperature of the exhaust air stream of the magnetron, where the temperature detection device is provided for the purpose of preventing damage to the apparatus caused by abnormal heat generated from the magnetron when the apparatus is operated while there is no heating object inside a heating chamber (for example, refer to PTL 1). FIG. 6 is a plan cross-sectional view illustrating a configuration of a conventional microwave oven. FIG. 6 illustrates a configuration in which a temperature detection device is attached to an air guide of the conventional microwave oven. As shown in FIG. 6, the microwave oven includes: heating chamber 1 accommodating a heating object; magnetron 2 supplying high frequency to heating chamber 1; cooling device 3 supplying a cooling air to heating chamber 1 and magnetron 2; air guide 4 guiding a cooling air used to cool magnetron 2 toward heating chamber 1; and temperature detection device 5 provided inside air guide 4 and detecting the temperature of a cooling air. Although not shown in the drawings, magnetron 2 includes an anode to which power is supplied and a cooling fin which is disposed inside an air stream path of the cooling air.
However, in the conventional configuration, the temperature of abnormal heat generated from magnetron 2 is transferred from the anode to the cooling fin, the cooling air flowing around the cooling fin is heated, and the temperature of the heated exhaust air stream is detected by temperature detection device 5. For this reason, there are problems that it takes time to thermally transfer the temperature of the abnormal heat to temperature detection device 5 and an abrupt increasing temperature may not be detected.
Further, since an allowance of a detection control level is ensured (an allowable range is set to be wide) in order to prevent erroneous detection due to the above-described reasons, a problem arises in reliability of a temperature control.
[PTL 1] Japanese Patent Unexamined Publication No. H06-185738